1. Field of the Invention
The present invention relates to an image forming apparatus and an image forming system forming an image by jetting liquid from nozzles.
2. Description of the Related Art
In an inkjet printing apparatus, in order to constantly maintain and recover a good ink jetting function, a suction mechanism which sucks a nozzle-surface discharges ink of which viscosity has increased in jetting nozzles (so-called purge operation). In an inkjet recording apparatus described in Japanese Patent Application Laid-open No. 9-109421, the maintenance or recovery operation is performed to a recording head or recording heads designated by a host computer, among a plurality of recording heads. Further, in an inkjet recording apparatus described in Japanese Patent Application Laid-open No. 7-68795, the suction recovery is performed only to a recording head or recording heads selected from a plurality of recording heads, under a suction condition such as an initial suction pressure, a suction amount, and a suction interval specifically set for each of the recording heads.
In an apparatus performing the maintenance or recovery operation at a predetermined cycle or the like, such as a typical inkjet printing apparatus, the maintenance or recovery operation is set on assumption that the worst state, among user's usage affecting the jetting performance of the recording head, would occur. Therefore, depending on the user's usage, ink is consumed more than necessary at the time of the maintenance or recovery operation.
For example, since the length of a power-off period cannot be usually measured, the recovery operation is performed when the apparatus is switched on based on the assumption that the apparatus has not been used for a long time. However, if a user frequently switches on/off the power by inserting/pulling a power plug, performing the recovery operation every time the apparatus is switched on results in wasteful ink consumption.
Further, viscosity increase of ink progresses differently depending on the use frequency of mediums, for example, depending on whether a large number of printing copies are frequently made, and setting the recovery operation according to a user whose use frequency of mediums is low results in wasteful ink consumption for a user who use mediums frequently.
Further, in an apparatus including a plurality of recording heads, ink not used by a user is also consumed by the maintenance or recovery operation performed at a predetermined cycle. Therefore, as described in Japanese Patent Application Laid-open No. 9-109421 and Japanese Patent Application Laid-open No. 7-68795, it has been proposed to set the maintenance or recovery operation according to the user's designation of a recording head or recording heads, thereby avoiding the consumption of a more than necessary amount of ink which has not been used much. However, in the apparatuses described in Japanese Patent Application Laid-open No. 9-109421 and Japanese Patent Application Laid-open No. 7-68795, since the maintenance or recovery operation is performed to the designated recording head or recording heads, the user has to check the printing result to judge whether the maintenance or recovery operation of each of the recording heads is necessary, or to adjust the setting for each of the recording heads according to printing data, which is difficult for an ordinary user.